STATE  PLANT  BOARD 


Issued  December  8.  1910. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 
BUREAU  OF  ENTOMOLOGY— CIRCULAR  No.  128. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


A.  D.  HOPKINS, 

In  Charge  of  Forest  Insect  Investigations. 


64135°  10  WASHINGTON  :  GOVERNMENT  PRINTING  OFRCE  :  1910 


A  ^3 


BUREAU  OF  EXTOMOLOGY. 


L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Assistant  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 
W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W,  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  QuAiNTANCE,  in  chavgc  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  hee  culture. 

D,  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 
RoLLA  P.  CuRRiE,  in  charge  of  editorial  toork. 

Mabel  Colcord,  librarian. 

Forest  Insect  Investigations. 

A.  D.  Hopkins,  in  charge. 

H.  E.  Burke,  J.  L.  Webb,  Josef  Brunner,  S.  A.  Roiiwer,  T.  E.  Snyder,  W.  D. 

Edmondston,  agents  and  experts. 
Mary  E.  Faunce,  preparator. 

William  Middleton,  Mary  C.  Johnson,  student  assistants. 
[Cir.  128] 
II 


Circular  No.  128. 


Issued  December  8,  1910. 


United  States  Department  of  Agriculture, 

BUREAU  OF  ENTOMOLOGY. 
L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 

INSECT  INJURIES  TO  FOREST  PRODUCTS." 

By  A.  D.  Hopkins, 
In  Charge  of  Forest  Insect  Investigations. 

Damage  is  caused  by  various  species  of  insects  which  are  attracted 
by  the  varying  conditions  prevailing  at  different  stages  during  the 
process  of  utilizing  the  forest  resources,  from  the  time  the  trees  are 
felled  until  the  logs  are  converted  into  the  crude  and  finished  product 
and  until  the  latter  reaches  the  final  consumer,  or  even  after  it  is 
placed  in  the  finished  article  or  structure.  As  a  result,  additional 
drains  are  made  on  the  timber  to  meet  the  demand  for  the  higher 
grades  of  lumber  and  for  other  supplies  to  replace  those  injured  or  * 
destroyed.  From  the  writer's  personal  investigations  of  this  subject 
in  different  sections  of  the  country  it  is  evident  that  the  damage  to 
forest  products  of  various  kinds  from  this  cause  is  far  more  extensive 
than  is  generally  recognized.  This  loss  differs  from  that  resulting 
from  insect  damage  to  standing  timber  in  that  it  represents  more 
directly  a  loss  of  money  invested  in  material  and  labor. 

CRUDE  PRODUCTS. 

Roundheaded  borers,  timber  worms,  and  ambrosia  beetles. — Round 
timber  with  the  bark  on,  such  as  poles,  posts,  mine  props,  saw  logs, 
etc.,  is  subject  to  serious  damage  by  the  same  class  of  insects  as  those 
mentioned  under  injury  to  the  wood  of  dying  and  dead  trees.  The 
damage  is  especially  severe  when  material  is  handled  in  such  a  man- 
ner as  to  offer  favorable  conditions  for  attack,  as  when  the  logs  are 
left  in  the  woods  on  skidways  or  in  millyards  for  a  month  or  more 
after  they  have  been  cut  from  the  living  trees.  Under  such  condi- 
tions there  is  often  a  reduction  in  value  of  from  5  to  30  per  cent  or 
more,  due  to  w^ormhole  and  pinhole  defects  caused  by  roundheaded 
and  flatheaded  wood-borers  and  timber  beetles.  Frequently  the 
insects  continue  the  work  in  the  unseasoned  and  even  dry  lumber 
cut  from  logs  which  had  been  previously  infested.    They  also  con- 


o  Revised  extracts  from  Bulletin  No.  58,  Part  V,  Bureau  of  Entomology,  U.  S. 
Department  of  Agriculture,  1909. 

64135° — Cir.  128—10  1 


2 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


tinue  to  work  in  mine  props  after  they  have  been  phiced  in  the  mine, 
and  in  logs  and  other  material  used  for  the  construction  of  cabins, 
rustic  houses,  etc..  and  in  round  timbers  generally. 

The  products  from  saplings,  such  as  hickor}^  hoop  poles  and  like 
material,  are  often  seriously  injured  or  rendered  worthless  by  round- 
headed  and  flatheaded  borers  and  wood-boring  beetles,  sometimes 
resulting  in  a  loss  of  from  50  to  100  per  cent  of  the  merchantable 
product. 

Stave  and  shingle  bolts  left  in  moist,  shady  places  in  the  woods  or 
in  close  piles  during  the  summer  months  are  often  attacked  by 
ambrosia  beetles  and  timber  beetles.  The  value  of  the  pro^luct  is 
often  reduced,  as  a  consequence,  from  10  to  50  per  cent  or  more. 

Handle  and  wagon  stock  in  the  rough  is  especially  liable  to  injury 
by  ambrosia  beetles  and  roundheaded  borers.  Hickory  and  ash  bolts 
from  which  the  bark  is  not  removed  are  almost  certain  to  be  greatly 
damaged  if  the  logs  and  bolts  cut  from  living  trees  during  the  winter 
and  spring  are  held  over  for  a  few  weeks  after  the  middle  of  March 
or  first  of  April. 

Pulp  wood,  and  cord  wood  for  fuel  and  other  purposes,  cut  during 
the  winter  and  spring  and  left  in  the  woods  for  a  few  weeks  or 
months  or  in  close  piles  after  the  beginning  of  the  warm  weather,  are 
sometimes  riddled  with  wormholes  or  converted  into  sawdust  borings, 
causing  a  loss  of  from  10  to  100  per  cent.  One  example  reported 
from  near  Munising,  Mich.,  represents  a  loss  of  $5,000  from  injury  to 
spruce  and  fir  pulp  wood  cut  in  the  winter  and  kept  in  piles  over 
summer. 

MANUFACTURED  UNSEASONED  PRODUCTS. 

Ambrosia  beetles  and  other  icood  borers. — Freshly  sawed  hard- 
wood placed  in  close  piles  during  warm,  damp  weather  during  the 
period  from  June  to  September  is  often  seriously  injured  by  am- 
brosia beetles.  Heavy  2-inch  to  3-inch  stuff  is  also  liable  to  attack 
by  the  same  insects,  even  in  loose  piles.  An  example  of  this  was 
found  in  some  thousands  of  feet  of  mahogany  lumber  of  the  highest 
grade,  which  had  been  sawed  from  imported  round  logs  and  piled 
with  lumber  sticks  between  the  tiers  of  plank.  Native  species  of 
ambrosia  beetles  had  entered  the  wood  to  such  an  extent  as  to  have  re- 
duced the  value  50  per  cent  or  more  within  a  few  weeks.  Oak,  poplar, 
gum,  and  similar  woods  often  sutfer  severely  from  this  class  of  injury, 
causing  losses  varying  from  5  to  50  per  cent. 

Lumber  and  square  timbers  of  both  soft  and  hard  woods  with  the 
bark  left  on  the  edges  are  frequently  damaged  by  flatlieaded  and 
roundheaded  wood  borers,  which  hatch  from  eggs  deposited  in  the 
bark  before  or  after  the  lumber  is  sawed.    There  are  examples  of 

ICIr.  lliSj 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


3 


losses  from  this  character  of  injury  amounting  to  from  20  to  50  per 
cent  or  more. 

Telegraph  and  telephone  poles,  posts,  mine  props,  etc.,  are  fre- 
quently injured  before  they  are  set  in  the  ground,  especially  if  the 
bark  remains  on  them  during  a  few  weeks  after  the  middle  of  March. 

SEASONED  PRODUCTS  IN  YARDS  AND  STOREHOUSES. 

Powder-post  heetles. — Hardwood  lumber  of  all  kinds,  rough 
handles,  wagon  stock,  etc.,  made  partially  or  entirely  of  sapwood,  are 
often  reduced  in  value  from  10  to  90  per  cent  by  a  class  of  insects 
known  as  powder-post  beetles.  The  sapwood  of  hickory,  ash,  and 
oak  is  most  liable  to  attack.  The  reported  losses  from  this  source 
during  the  past  five  or  six  years  indicate  that  there  has  been  an 
average  reduction  in  values  of  from  5  to  10  per  cent  or  more. 

Old  hemlock  and  oak  tanbark  is  often  so  badly  damaged  by  vari- 
ous insects  which  infest  dead  and  dry  bark  that  in  some  tanyards  as 
much  as  50  to  75  per  cent  of  the  bark  that  is  over  three  years  old  is 
destroyed.  In  one  tannery  in  West  Virginia  it  is  estimated  that  more 
than  $30,000  worth  of  hemlock  bark  was  thus  destroyed. 

FINISHED  PRODUCTS. 

The  greatest  loss  of  finished  hardwood  products,  such  as  handle, 
wagon,  carriage,  and  machinery  stock,  is  caused  by  powder-post 
beetles.  This  is  especially  true  of  hickory  and  ash  handles  and  like 
products  in  the  large  and  small  storehouses  of  the  country,  including 
the  vast  amount  of  material  held  in  storage  for  the  army  and  navy. 
When  material  of  this  kind  is  once  attacked  it  is  usually  worthless 
for  the  purposes  indicated,  and  therefore  must  be  replaced  with  new 
material.  In  some  cases  losses  have  amounted  to  from  10  to  50  per 
cent,  and  it  is  estimated  that  the  average  losses  have  been  as  much  as 
10  per  cent  on  nearly  all  sapwood  material  that  has  been  in  storage 
more  than  one  year. 

UTILIZED  PRODUCTS. 

Powder-post  hettles^  white  ants,  and  other  wood-horing  insects. — 
The  finished  woodwork  in  implements,  machinery,  wagons,  furniture, 
and  the  inside  finish  in  private  and  public  buildings  are  often  seri- 
ously damaged  by  powder-post  beetles,  thus  requiring  increased  de- 
mands for  new  material. 

Construction  timbers  and  other  woodwork  in  new  and  old  build- 
ings are  often  so  seriously  damaged  by  powder-post  beetles,  white 
ants,  and  other  wood-boring  insects  that  the  affected  material  has  to 
be  removed  and  replaced  by  new,  or  the  entire  structure  torn  down 
and  rebuilt. 

[Cir.  128] 

LIBRARY 

grATE  pi-ant  board 


4 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


Construction  timbers  in  bridges  and  like  structures,  railroad  ties, 
telephone  and  telegraph  poles,  mine  props,  fence  posts,  etc.,  are  some- 
times seriously  injured  by  wood-boring  larvae,  termites,  black  ants, 
carpenter  bees,  and  powder-post  beetles,  and  sometimes  reduced  in 
value  from  10  to  100  per  cent. 

PREVENTION   OF  INSECT  INJURIES  TO  FOREST  PRODUCTS. 

The  problem  of  artificial  control  and  prevention  of  insect  injuries 
to  forest  products  offers  less  difficulties  perhaps  than  that  relating 
to  many  other  branches  of  the  general  subject  of  forest-insect  control. 
In  most  cases  the  principle  of  prevention  is  the  only  one  to  be  con- 
sidered, since  the  damage  is  done  soon  after  the  insects  enter  the 
wood,  and  therefore  it  can  not  be  repaired  by  destroying  the  enemy. 

Crude  Products. 

The  proper  degree  of  moisture  found  in  the  bark  and  wood  of 
newly  felled  trees,  saw  logs,  telegraph  poles,  posts,  and  like  material, 
cut  in  the  fall  and  winter  and  left  on  the  ground  or  in  close  piles 
during  a  few  weeks  or  months  in  the  spring  and  summer  or  during 
the  period  when  the  particular  species  of  injurious  insects  are  flying, 
are  some  of  the  conditions  most  favorable  to  attack.  The  period  of 
danger  varies  Avith  the  kind  of  timber  and  the  time  of  the  year  it  is 
felled.  Those  felled  in  late  fall  and  winter  will  generally  remain 
attractive  to  ambrosia  beetles  and  adults  of  round  and  flat  headed 
borers  during  March,  April,  and  May.  Those  felled  during  the 
period  between  April  and  September  may  be  attacked  in  a  few  days 
after  they  are  felled,  but  the  period  of  danger  from  a  given  species 
of  insect  may  not  extend  over  more  than  a  few  weeks.  Thus  certain 
kinds  of  trees  felled  during  certain  seasons  are  never  attacked,  while 
if  they  are  felled  at  other  times  and  seasons  the  conditions  for  attack 
may  be  most  favorable  when  the  insects  are  active,  and  then  the  wood 
will  be  thickly  infested  and  ruined.  The  presence  of  bark  is  abso- 
lutely necessary  for  successful  infestation  by  most  of  the  wood-boring 
grubs,  because  the  eggs  and  young  stages  must  occupy  the  inner 
<in(l  outer  portions  before  the  latter  can  enter  the  wood.  Some 
aiiiljrosia  beetles  and  timber  Avorms  will,  however,  attack  barked  logs, 
especially  those  in  close  piles  or  otherwise  shaded  or  protected  from 
rapid  drjnng.  A  large  percentage  of  tlie  injuTV  to  this  class  of 
products  can  be  prevented,  as  follows: 

(1)  Provide  for  as  little  delay  ns  possible  between  the  felling  of  the 
tree  and  its  manufacture  into  rough  products.  This  is  especially 
necessary  with  trees  felled  from  Aj^ril  to  September  in  the  region 
jiortli  of  the  (iulf  States  and  from  March  to  November  in  the  latter, 

(Clr.  IL'8] 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


5 


while  the  late  fall  and  winter  cuttings  should  all  be  worked  up  by 
March  or  April. 

(2)  Do  not  leave  the  round  timbers  in  the  woods  or  on  the  skid- 
ways  during  the  danger  period,  or,  if  this  is  unavoidable,  take  every 
precaution  to  facilitate  the  rapid  drying  of  the  inner  bark  by  keeping 
the  logs  off  the  ground,  in  the  sun,  or  in  loose  piles,  or  else,  if  possible, 
the  opposite  extreme  should  be  adopted  and  the  logs  kept  in  water. 

(3)  Remove  the  bark  within  a  few  days  after  the  trees  are  felled, 
from  poles,  posts,  and  other  material  which  will  not  be  injured  by 
checking  or  season  cracks. 

(4)  Take  advantage  of  the  proper  months  or  seasons  in  which  to 
fell  or  girdle  different  kinds  of  trees  to  avoid  danger. 

Damage  to  products  cut  from  saplings  and  left  with  the  bark  on 
can  be  prevented  by  transporting  the  material  from  the  woods  soon 
after  it  is  cut,  so  that  it  will  not  be  left  in  piles  or  bundles  in  or  near 
the  forest  during  the  season  of  insect  activity.  Damage  may  also  be 
prevented  if  care  is  taken  not  to  leave  the  material  stored  in  one  place 
for  several  months. 

Pinhole  damage  to  stave  and  shingle  bolts  cut  during  a  warm  season 
can  be  prevented  by  removing  the  bark  from  the  timber  as  soon  as  it 
is  felled  and  by  converting  the  bolts  into  the  smallest  practicable 
dimensions  and  piling  them  in  such  a  manner  as  to  facilitate  rapid 
drying. 

Damage  to  unseasoned  handle  and  wagon  stock  in  the  rough  can  be 
prevented  by  taking  special  precautions  to  provide  against  the  same 
favorable  conditions  for  attack  as  mentioned  in  connection  with  round 
timbers.  This  is  especially  necessary  with  hickory  and  ash  if  cut 
during  the  winter  and  spring. 

Damage  to  pulpwood  and  cordwood  can  be  prevented  to  a  great 
extent  by  placing  the  sticks  of  wood  in  triangular  or  crib  piles  imme- 
diately after  they  are  cut  from  the  trees,  especially  if  the  timber  is  cut 
during  the  danger  period,  or  must  be  held  for  a  few  months  during  the 
warm  season.  Peeling  or  splitting  the  wood,  or  both,  before  it  is 
piled  will  also  provide  against  damage  from  insects. 

Manufactured  Tkoducts. 
unseasoned  products. 

Freshly  sawed  hardwood  lumber  placed  in  close  piles  during  warm, 
damp  weather  in  the  period  from  July  to  September,  inclusive,  pre- 
sents the  most  favorable  conditions  for  injury  by  ambrosia  beetles. 
In  all  cases  it  is  the  moist  condition  and  retarded  drying  of  the  lum- 
ber which  induces  attack.  Therefore  any  method  which  will  provide 
for  the  rapid  drying  of  the  lumber  before  or  after  piling  will  tend 

[Cir.  128] 


6 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


to  prevent  loss.  It  is  imiDortant,  also,  that  heavy  lumber  should, 
as  far  as  possible,  be  cut  only  in  the  winter  and  piled  so  that  it  will 
be  well  dried  out  before  the  middle  of  March. 

The  damage  to  lumber  and  square  timber  when  the  bark  is  left  on 
the  edges  or  sides  can  be  prevented  by  removing  the  bark  before  or 
immediately  after  the  lumber  is  sawed,  or  by  sawing  and  piling  the 
material  during  the  winter,-  or  if  sawed  at  other  times  it  should  be 
piled  so  that  rapid  drying  will  be  facilitated. 

SEASONED  PRODUCTS. 

Unfinished  seasoned  products. — Injury  by  powder-post  beetles  to 
dry  hardwood  lumber  and  other  material  in  stacks  or  storehouses  can 
be  prevented  as  follows : 

(1)  Have  a  general  inspection  of  the  material  in  the  yards  and 
storehouses  at  least  once  a  year^  preferably  during  November  or 
February,  for  the  purpose  of  (a)  sorting  out  and  destroying  or  other- 
wise disposing  of  any  material  that  shows  the  slightest  evidence  of 
injury,  as  indicated  by  the  presence  of  fine  powdery  boring  dust,  and 
(6)  sorting  out  and  destroying  all  old  and  useless  sapwood  material 
of  any  kind  that  will  offer  favorable  breeding  places  for  the  insects. 

(2)  Prevent  the  introduction  into  the  lumber  j'ards  or  storehouses 
of  any  infested  material,  remembering  that  the  insect  may  be  thus 
distributed  to  or  from  all  parts  of  the  world. 

(3)  Adopt  a  system  of  classification  of  all  dry  or  seasoned  hard- 
wood stock  which  will  provide  for  {a)  the  separation  of  the  pure 
heartwood  material  from  the  pure  and  part  sapwood  material;  {b) 
classification  of  all  kinds  of  wood  most  liable  to  attack,  such  as  hick- 
ory, ash,  oak;  (c)  the  successive  utilization  or  sale  of  the  older  ma- 
terial (remembering  that  material  one  year  old  or  over  is  far  more 
liable  to  injury)  ;  {d)  providing  against  the  accumulation  of  refuse 
material  in  which  the  insects  could  breed;  and  {e)  treating  the  best 
material  with  linseed  oil  or  kerosene  to  prevent  attack. 

Finished  seasoned  products. — Damage  to  finished  handles,  oars, 
spokes,  rims,  hubs,  wheels,  and  other  unpainted  wagon,  carriage, 
machinery,  and  implement  stock  in  factories,  wholesale  and  retail 
storehouses,  and  army  and  navy  stores  can  be  prevented  by  the  adop- 
tion of  the  same  general  ndes  as  those  given  under  rough  products. 
In  addition,  damage  can  be  controlled  and  prevented  in  the  following 
manner: 

Sort  out  and  {a)  destroy  all  articles  vshowing  the  slightest  evidence 
of  p(>W(ler-i)()st  injury,  or  (/>)  treat  with  kerosene  oil  such  infested 
and  slightly  injured  articles  as  may  be  tested  for  required  strength 
and  found  to  be  of  sullicient  value  for  retention,  placing  the  same  in 
<|uarantine  for  a  sullicient  time  to  determine  whether  the  treatment  is 
sncccssfid. 

ICir.  1-8] 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


7 


Damage  b}^  powder-post  insects  to  many  kinds  of  articles  can  be  pre- 
vented and  at  the  same  time  the  material  otherwise  benefited  by  treat- 
ing the  sapwood  with  linseed  oil  or  kerosene,  either  by  immersing  it 
in  the  oil  or  by  applying  the  oil  with  a  brush,  the  application  to  be 
made  as  soon  as  possible  after  the  articles  are  finished  from  recently 
seasoned,  uninjured  stock. 

Past  and  Present  Conditions  of  Powder-Post  Injury. 

Up  to  1906  there  were  a  great  many  reports  of  extensive  losses  of 
valuable  material  from  the  ravages  of  powder-post  beetles  which 
were  seriousl}-  affecting  all  industries  involved  in  the  manufacture, 
sale,  and  utilization  of  the  classes  of  hardwood  products  affected  by 
them.  In  response  to  these  reports  and  accompanying  appeals  to  the 
Department  of  Agriculture  for  information  on  causes  and  remedies, 
the  i^roblem  was  thoroughly  investigated  and  specific  advice  and  in- 
structions relating  to  practical  methods  of  control  and  prevention 
have  been  widely  disseminated,  both  through  publications  of  the 
Department  and  special  correspondence. 

Reports  of  present  conditions  from  our  principal  correspondents, 
together  with  the  less  frequent  requests  for  advice,  indicate  that 
the  disseminated  information  has  been  extensively  utilized  and  that 
it  has  been  worth  many  millions  of  dollars  toward  eliminating  the 
losses  and  reducing  the  drain  on  the  limited  supply  of  the  kinds  of 
timber  required  to  replenish  the  damaged  and  destroyed  material. 

The  army  and  navy  stores  of  handles,  tent  poles,  wheelbarrows, 
oars,  and  many  other  hardwood  articles  have  suffered  severely  from 
powder-post  damage,  involving  an  enormous  loss,  but  the  carrying 
out  of  the  information  already  supplied  has  evidently  contributed 
greatly  toward  the  elimination  of  this  source  of  loss  to  the  Gov- 
ernment. 

Tan  Park. 

Damage  to  hemlock  and  oak  tan  bark  by  the  class  of  insects  which 
in  some  cases  has  been  so  destructive  to  these  products  in  the  past  can 
be  easily  prevented  without  cost,  as  follows: 

(1)  Utilize  the  bark  within  three  years  from  the  time  it  is  taken 
from  the  trees. 

(2)  Prevent  the  accumulation  in  the  yards  and  store  sheds  of  old 
bark  and  waste  material  in  which  the  insects  can  breed. 

These  simple  methods  have  been  extensively  adopted  since  their 
recommendation  in  correspondence  and  publications  between  about 
1894  and  1904,  and  afford  one  of  the  most  striking  examples  of  the 
value  of  expert  information  on  the  peculiar  habits  of  insects  and  of 
how  millions  of  dollars  can  be  saved  without  cost  through  a  simple 
adjustment  in  methods  of  utilization. 

[Cir.  128] 


8 


INSECT  INJURIES  TO  FOEEST  PRODUCTS. 


Utilized  Products. 

Damage  and  loss  from  insect  injuries  to  timber  and  other  ^YOodwork 
in  structures  of  various  kinds,  to  telephone  and  telegraph  poles,  posts, 
railroad  ties,  mine  props,  etc.,  can  be  prevented  to  a  large  extent 
through  the  adoption  of  the  proper  methods  of  management  or  of 
treating  the  material  with  preservatives  before  and  after  it  is  utilized. 

TIMBERS  AND  WOODWORK  IN  STRUCTURES. 

Injuries  to  timbers  and  woodwork  in  dwellings,  outbuildings, 
bridges,  etc.,  by  powder-post  insects  can  be  prevented  as  follows: 

( 1 )  Use  nothing  but  heartwood  for  the  concealed  parts  most  liable 
to  damage. 

(2)  If  it  is  necessary  to  use  all  or  part  sapwood  material,  attack 
can  be  prevented  by  treating  the  sap  portions  Avith  kerosene,  coal  tar, 
creosote,  or  linseed  oil.  Facilities  for  future  treatment  can  be  pro- 
vided wherever  the  rough  or  finished  Avoodwork  is  exposed,  as  in 
outbuildings,  bridges,  etc.,  if  care  is  taken  to  expose  the  sapwood 
portions. 

(3)  If  the  untreated  timbers  and  woodwork  in  old  buildings  show 
evidence  of  attack,  the  affected  portions  should  be  given  a  liberal 
application  of  kerosene. 

Damage  by  white  ants,  or  termites,  can  often  be  prevented  in  the 
following  ways : 

(1)  By  the  use  of  nothing  but  sound  wood  for  underpinning  and 
foundation  timbers  and  the  removal  of  decaying  timbers  from  old 
structures. 

(2)  By  preventing  moist  conditions  of  the  wood  in  any  i)art  of  the 
structure  and  especially  that  in  foundation  timbers. 

(3)  By  the  treatment  of  timbers  necessarily  exposed  to  moist  con- 
ditions with  creosote,  zinc  chlorid,  corrosive  sublimate,  etc. 

(4)  If  the  timbers  become  infested,  further  progress  of  insect  dam- 
age can  be  prevented  by  removing  the  badly  damaged  parts  and  soak- 
ing the  remainder  with  kerosene,  fumigating  with  bisulphid  of 
carbon,  and  by  removing  any  adjacent  decaying  or  other  wood  in 
which  the  insects  have  been  breeding  or  may  breed,  such  as  logs, 
stumps,  etc. 

!.()()  cahins  and  imHtic  work. — Damage  by  bark  and  wood  boring 
insects  to  the  unbarked  logs  and  poles  used  in  rustic  cabins,  summer 
houses,  fences,  etc.,  can  be  largely  prevented  by  cutting  the  matei'ial 
in  October  and  November  and  utilizing  it  at  once,  or  by  piling  it  off 
the  ground  or  under  cover  in  such  n  manner  as  to  offer  the  best  facil- 
ities for  the  rapid  and  thorough  drying  of  the  inner  bark  before  the 
middle  of  March  or  the  1st  of  April  following.    If  these  necessary 

[(Mr.  rJHJ 


INSECT  INJURIES  TO  FOREST  PRODUCTS. 


9 


precautions  are  not  taken,  and  there  is  evidence  that  insects  are  at 
work  in  the  bark  and  wood,  the  damage  can  be  checked  by  injecting 
bisulphid  of  carbon  through  natural  or  artificial  openings  in  the 
affected  bark,  and  immediately  stopping  these  and  other  openings 
with  putty  or  a  similar  substance. 

Poles^  posts,  piles,  ties,  mine  props,  and  similar  products. — Insect 
damage  to  poles,  posts,  and  similar  products  can  be  prevented  to  a 
greater  or  less  extent  by  the  preservative  treatments  which  have  been 
tested  and  recommended  by  the  Forest  Service  for  the  prevention  of 
decay.  These  should  be  applied  before  the  material  is  utilized  for 
the  purposes  intended,  or,  if  it  be  attacked  after  it  has  been  utilized, 
further  damage  can  be  checked  to  a  certain  extent  by  the  use  of  the 
same  substances. 

It  is  often  of  prime  importance  to  prevent  injury  from  wood- 
boring  insects,  for  the  reason  that  such  injuries  contribute  to  more 
rapid  decay.  Therefore  anything  that  will  prevent  insect  injury, 
either  before  or  after  the  utilization  of  such  products,  will  contribute 
to  the  prevention  of  premature  deterioration  and  decay. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  October  7, 1910. 

[Cir.  128] 


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